Re: [PATCH v2 3/3] selftests/x86, x86/ldt: Add a selftest for modify_ldt
On Tue, Jul 21, 2015 at 4:36 PM, Willy Tarreau wrote:
> Hi Andy,
>
> On Tue, Jul 21, 2015 at 12:59:31PM -0700, Andy Lutomirski wrote:
>> This tests general modify_ldt behavior (only writes, so far) as
>> well as synchronous updates via IPI. It fails on old kernels.
>>
>> I called this ldt_gdt because I'll add set_thread_area tests to
>> it at some point.
>
> Quick feedback : at two places you have this :
>
>> + } else if (errno == ENOSYS) {
>> + printf("[OK]\tmodify_ldt is returned -ENOSYS\n");
>
> => s/is //
>
> Please add stdlib.h to avoid this warning I'm getting on 32-bit :
>
> ldt_gdt.c:286:4: warning: incompatible implicit declaration of built-in
> function 'exit' [enabled by default]
>
> And I had to remove xmmintrinsic as suggested by Boris as well.
>
>
> FWIW here's what I'm getting here on 4.1.2 without CONFIG_X86_16BIT
> (where nmi_espfix failed), the output is the same for a 32- and a 64-bit
> process :
>
> [OK]LDT entry 0 has AR 0x0040FA00 and limit 0x000A
> [OK]LDT entry 0 has AR 0x00C0FA00 and limit 0xAFFF
> [OK]LDT entry 1 is invalid
> [OK]LDT entry 2 has AR 0x00C0FA00 and limit 0xAFFF
> [OK]LDT entry 1 is invalid
> [OK]LDT entry 2 has AR 0x00C0FA00 and limit 0xAFFF
> [OK]LDT entry 2 has AR 0x00D0FA00 and limit 0xAFFF
> [OK]LDT entry 2 has AR 0x00D07A00 and limit 0xAFFF
> [OK]modify_ldt rejected 16 bit segment
> [OK]LDT entry 2 has AR 0x00D07200 and limit 0xAFFF
> [OK]LDT entry 2 has AR 0x00D07000 and limit 0xAFFF
> [OK]LDT entry 2 has AR 0x00D07400 and limit 0xAFFF
> [OK]LDT entry 2 has AR 0x00507600 and limit 0x000A
> [OK]LDT entry 2 has AR 0x00507E00 and limit 0x000A
> [OK]LDT entry 2 has AR 0x00507C00 and limit 0x000A
> [OK]LDT entry 2 has AR 0x00507A00 and limit 0x000A
> [OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
> [OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
> [RUN] Test fork
> [OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
> [OK]LDT entry 1 is invalid
> [OK]Child succeeded
> [OK]modify_ldt failure 22
> [OK]modify_ldt rejected 16 bit segment
> [OK]modify_ldt rejected 16 bit segment
> [OK]modify_ldt rejected 16 bit segment
> [OK]modify_ldt rejected 16 bit segment
> [OK]modify_ldt rejected 16 bit segment
> [OK]modify_ldt rejected 16 bit segment
> [OK]LDT entry 0 is invalid
> [OK]LDT entry 0 has AR 0x0040F200 and limit 0x
> [OK]LDT entry 0 is invalid
> [RUN] Cross-CPU LDT invalidation
> [FAIL] 5 of 5 iterations failed
That's intentional. Old modify_ldt can leave other threads with stale
cached descriptors, which is what you're seeing.
--Andy
>
> Thanks,
> Willy
>
--
Andy Lutomirski
AMA Capital Management, LLC
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Re: [PATCH v2 3/3] selftests/x86, x86/ldt: Add a selftest for modify_ldt
Hi Andy,
On Tue, Jul 21, 2015 at 12:59:31PM -0700, Andy Lutomirski wrote:
> This tests general modify_ldt behavior (only writes, so far) as
> well as synchronous updates via IPI. It fails on old kernels.
>
> I called this ldt_gdt because I'll add set_thread_area tests to
> it at some point.
Quick feedback : at two places you have this :
> + } else if (errno == ENOSYS) {
> + printf("[OK]\tmodify_ldt is returned -ENOSYS\n");
=> s/is //
Please add stdlib.h to avoid this warning I'm getting on 32-bit :
ldt_gdt.c:286:4: warning: incompatible implicit declaration of built-in
function 'exit' [enabled by default]
And I had to remove xmmintrinsic as suggested by Boris as well.
FWIW here's what I'm getting here on 4.1.2 without CONFIG_X86_16BIT
(where nmi_espfix failed), the output is the same for a 32- and a 64-bit
process :
[OK]LDT entry 0 has AR 0x0040FA00 and limit 0x000A
[OK]LDT entry 0 has AR 0x00C0FA00 and limit 0xAFFF
[OK]LDT entry 1 is invalid
[OK]LDT entry 2 has AR 0x00C0FA00 and limit 0xAFFF
[OK]LDT entry 1 is invalid
[OK]LDT entry 2 has AR 0x00C0FA00 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D0FA00 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D07A00 and limit 0xAFFF
[OK]modify_ldt rejected 16 bit segment
[OK]LDT entry 2 has AR 0x00D07200 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D07000 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D07400 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00507600 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507E00 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507C00 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507A00 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
[RUN] Test fork
[OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
[OK]LDT entry 1 is invalid
[OK]Child succeeded
[OK]modify_ldt failure 22
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]LDT entry 0 is invalid
[OK]LDT entry 0 has AR 0x0040F200 and limit 0x
[OK]LDT entry 0 is invalid
[RUN] Cross-CPU LDT invalidation
[FAIL] 5 of 5 iterations failed
Thanks,
Willy
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Re: [PATCH v2 3/3] selftests/x86, x86/ldt: Add a selftest for modify_ldt
On Tue, Jul 21, 2015 at 3:02 PM, Boris Ostrovsky wrote: > On 07/21/2015 03:59 PM, Andy Lutomirski wrote: >> >> diff --git a/tools/testing/selftests/x86/ldt_gdt.c >> b/tools/testing/selftests/x86/ldt_gdt.c >> new file mode 100644 >> index ..6f6699f0351a >> --- /dev/null >> +++ b/tools/testing/selftests/x86/ldt_gdt.c >> @@ -0,0 +1,492 @@ >> +/* >> + * ldt_gdt.c - Test cases for LDT and GDT access >> + * Copyright (c) 2015 Andrew Lutomirski >> + */ >> + >> +#define _GNU_SOURCE >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include > > > Is xmmintrin.h necessary? It breaks 32-bit build with no, and I'll remove it. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v2 3/3] selftests/x86, x86/ldt: Add a selftest for modify_ldt
On 07/21/2015 03:59 PM, Andy Lutomirski wrote: diff --git a/tools/testing/selftests/x86/ldt_gdt.c b/tools/testing/selftests/x86/ldt_gdt.c new file mode 100644 index ..6f6699f0351a --- /dev/null +++ b/tools/testing/selftests/x86/ldt_gdt.c @@ -0,0 +1,492 @@ +/* + * ldt_gdt.c - Test cases for LDT and GDT access + * Copyright (c) 2015 Andrew Lutomirski + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include Is xmmintrin.h necessary? It breaks 32-bit build with /usr/lib/gcc/x86_64-redhat-linux/4.7.2/include/xmmintrin.h:32:3: error: #error "SSE instruction set not enabled" unless I add -msse2. (This also needs stdlib.h for exit() declaration) -boris -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v2 3/3] selftests/x86, x86/ldt: Add a selftest for modify_ldt
On 07/21/2015 03:59 PM, Andy Lutomirski wrote: diff --git a/tools/testing/selftests/x86/ldt_gdt.c b/tools/testing/selftests/x86/ldt_gdt.c new file mode 100644 index ..6f6699f0351a --- /dev/null +++ b/tools/testing/selftests/x86/ldt_gdt.c @@ -0,0 +1,492 @@ +/* + * ldt_gdt.c - Test cases for LDT and GDT access + * Copyright (c) 2015 Andrew Lutomirski + */ + +#define _GNU_SOURCE +#include err.h +#include stdio.h +#include stdint.h +#include signal.h +#include setjmp.h +#include string.h +#include errno.h +#include xmmintrin.h Is xmmintrin.h necessary? It breaks 32-bit build with /usr/lib/gcc/x86_64-redhat-linux/4.7.2/include/xmmintrin.h:32:3: error: #error SSE instruction set not enabled unless I add -msse2. (This also needs stdlib.h for exit() declaration) -boris -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v2 3/3] selftests/x86, x86/ldt: Add a selftest for modify_ldt
On Tue, Jul 21, 2015 at 3:02 PM, Boris Ostrovsky boris.ostrov...@oracle.com wrote: On 07/21/2015 03:59 PM, Andy Lutomirski wrote: diff --git a/tools/testing/selftests/x86/ldt_gdt.c b/tools/testing/selftests/x86/ldt_gdt.c new file mode 100644 index ..6f6699f0351a --- /dev/null +++ b/tools/testing/selftests/x86/ldt_gdt.c @@ -0,0 +1,492 @@ +/* + * ldt_gdt.c - Test cases for LDT and GDT access + * Copyright (c) 2015 Andrew Lutomirski + */ + +#define _GNU_SOURCE +#include err.h +#include stdio.h +#include stdint.h +#include signal.h +#include setjmp.h +#include string.h +#include errno.h +#include xmmintrin.h Is xmmintrin.h necessary? It breaks 32-bit build with no, and I'll remove it. --Andy -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH v2 3/3] selftests/x86, x86/ldt: Add a selftest for modify_ldt
Hi Andy,
On Tue, Jul 21, 2015 at 12:59:31PM -0700, Andy Lutomirski wrote:
This tests general modify_ldt behavior (only writes, so far) as
well as synchronous updates via IPI. It fails on old kernels.
I called this ldt_gdt because I'll add set_thread_area tests to
it at some point.
Quick feedback : at two places you have this :
+ } else if (errno == ENOSYS) {
+ printf([OK]\tmodify_ldt is returned -ENOSYS\n);
= s/is //
Please add stdlib.h to avoid this warning I'm getting on 32-bit :
ldt_gdt.c:286:4: warning: incompatible implicit declaration of built-in
function 'exit' [enabled by default]
And I had to remove xmmintrinsic as suggested by Boris as well.
FWIW here's what I'm getting here on 4.1.2 without CONFIG_X86_16BIT
(where nmi_espfix failed), the output is the same for a 32- and a 64-bit
process :
[OK]LDT entry 0 has AR 0x0040FA00 and limit 0x000A
[OK]LDT entry 0 has AR 0x00C0FA00 and limit 0xAFFF
[OK]LDT entry 1 is invalid
[OK]LDT entry 2 has AR 0x00C0FA00 and limit 0xAFFF
[OK]LDT entry 1 is invalid
[OK]LDT entry 2 has AR 0x00C0FA00 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D0FA00 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D07A00 and limit 0xAFFF
[OK]modify_ldt rejected 16 bit segment
[OK]LDT entry 2 has AR 0x00D07200 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D07000 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D07400 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00507600 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507E00 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507C00 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507A00 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
[RUN] Test fork
[OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
[OK]LDT entry 1 is invalid
[OK]Child succeeded
[OK]modify_ldt failure 22
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]LDT entry 0 is invalid
[OK]LDT entry 0 has AR 0x0040F200 and limit 0x
[OK]LDT entry 0 is invalid
[RUN] Cross-CPU LDT invalidation
[FAIL] 5 of 5 iterations failed
Thanks,
Willy
--
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the body of a message to majord...@vger.kernel.org
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Re: [PATCH v2 3/3] selftests/x86, x86/ldt: Add a selftest for modify_ldt
On Tue, Jul 21, 2015 at 4:36 PM, Willy Tarreau w...@1wt.eu wrote:
Hi Andy,
On Tue, Jul 21, 2015 at 12:59:31PM -0700, Andy Lutomirski wrote:
This tests general modify_ldt behavior (only writes, so far) as
well as synchronous updates via IPI. It fails on old kernels.
I called this ldt_gdt because I'll add set_thread_area tests to
it at some point.
Quick feedback : at two places you have this :
+ } else if (errno == ENOSYS) {
+ printf([OK]\tmodify_ldt is returned -ENOSYS\n);
= s/is //
Please add stdlib.h to avoid this warning I'm getting on 32-bit :
ldt_gdt.c:286:4: warning: incompatible implicit declaration of built-in
function 'exit' [enabled by default]
And I had to remove xmmintrinsic as suggested by Boris as well.
FWIW here's what I'm getting here on 4.1.2 without CONFIG_X86_16BIT
(where nmi_espfix failed), the output is the same for a 32- and a 64-bit
process :
[OK]LDT entry 0 has AR 0x0040FA00 and limit 0x000A
[OK]LDT entry 0 has AR 0x00C0FA00 and limit 0xAFFF
[OK]LDT entry 1 is invalid
[OK]LDT entry 2 has AR 0x00C0FA00 and limit 0xAFFF
[OK]LDT entry 1 is invalid
[OK]LDT entry 2 has AR 0x00C0FA00 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D0FA00 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D07A00 and limit 0xAFFF
[OK]modify_ldt rejected 16 bit segment
[OK]LDT entry 2 has AR 0x00D07200 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D07000 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00D07400 and limit 0xAFFF
[OK]LDT entry 2 has AR 0x00507600 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507E00 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507C00 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507A00 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
[OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
[RUN] Test fork
[OK]LDT entry 2 has AR 0x00507800 and limit 0x000A
[OK]LDT entry 1 is invalid
[OK]Child succeeded
[OK]modify_ldt failure 22
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]modify_ldt rejected 16 bit segment
[OK]LDT entry 0 is invalid
[OK]LDT entry 0 has AR 0x0040F200 and limit 0x
[OK]LDT entry 0 is invalid
[RUN] Cross-CPU LDT invalidation
[FAIL] 5 of 5 iterations failed
That's intentional. Old modify_ldt can leave other threads with stale
cached descriptors, which is what you're seeing.
--Andy
Thanks,
Willy
--
Andy Lutomirski
AMA Capital Management, LLC
--
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the body of a message to majord...@vger.kernel.org
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